IPC Subgroup
C01B 21/2 Nitrogen oxides; Oxyacids of nitrogen; Salts thereof
Introduced: September 1968
Last revised: January 2006
Full Title
Nitrogen; Compounds thereof > Nitrogen oxides; Oxyacids of nitrogen; Salts thereof
Classification Context
- Section:
- CHEMISTRY; METALLURGY
- Class:
- INORGANIC CHEMISTRY
- Subclass:
- NON-METALLIC ELEMENTS; COMPOUNDS THEREOF
Related Keywords
HYPONITROUS [acid]NITROGEN oxides
7 direct subcodes
Child Classifications
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- C01B 21/22 Nitrous oxide (NO)
- C01B 21/24 Nitric oxide (NO)
- C01B 21/34 Nitrogen trioxide (NO)
- C01B 21/36 Nitrogen dioxide (NO, NO)
- C01B 21/38 Nitric acid
- C01B 21/48 Methods for the preparation of nitrates in general
- C01B 21/5 Nitrous acid; Salts thereof
Top Applicants
Top 10 applicants by patent filingsfor class C01, 2013–2023, worldwide · Source: EPO PATSTAT
- CHINESE ACADEMY OF SCIENCES 5,794
- SINOPEC (CHINA PETROCHEMICAL CORPORATION) 3,286
- LG CHEM KR 2,689
- BASF (BADISCHE ANILIN & SODA FABRIK) DE 1,669
- CENTRAL SOUTH UNIVERSITY 1,531
- KMUST (KUNMING UNIVERSITY OF SCIENCE AND TECHNOLOGY) 1,252
- SUMITOMO METAL MINING COMPANY JP 1,073
- ZHEJIANG UNIVERSITY 1,061
- PANASONIC INTELLECTUAL PROPERTY JP 1,058
- PANASONIC INTELLECTUAL PROPERTY 1,038